IPhone is a perfect all around device for teachers. I like the convenience of having my weekly lectures timetable with me at all times, together with the ability to dynamically move classes around, keep track of appointments, etc. That is for the organisational perspective. As far as educational matters are concerned, the benefits depend on the content of your lessons: would you be likely to play a lot of video/audio files in class? If so, iPhone can help too - since you are able to connect it to a set of speakers or a projector to play presentations in class. It really makes some tasks easier and/or more intuitive, but the ability to keep organised ultimately clinched it for me.